Magnetizing device with reduced stray field

Abstract

A magnetizing device includes a magnet and a magnetic field concentrator. The magnet has a magnetic field forming a magnetization region in which a magnetizable security element is exposed to a magnetic field strength having a defined magnetic field direction. The magnetic field concentrator is formed of a ferromagnetic material. The magnetic field concentrator is arranged in the magnetic field and amplifies and focuses the magnetic field in the magnetization region.

What is claimed is: 
     
       1. A magnetizing device, comprising:
 a first magnet having a magnetic field forming a magnetization region in which a magnetizable security element is transported in a transport direction through the magnetization region and exposed to a magnetic field strength having a defined magnetic field direction, wherein the magnetic field is tangential to the transport direction of the magnetizable security element on an upper side and a lower side of the magnetizable security element; and 
 a first magnetic field concentrator formed of a ferromagnetic material, the first magnetic field concentrator is arranged in the magnetic field and adapted to focus and amplify the magnetic field in the defined magnetic field direction in the magnetization region to result in a stronger magnetic field on one of an upper side and a lower side of the magnetizable security element. 
 
     
     
       2. The magnetizing device of  claim 1 , wherein the first magnet is a permanent magnet. 
     
     
       3. The magnetizing device of  claim 2 , wherein the first magnet has a block shape. 
     
     
       4. The magnetizing device of  claim 1 , wherein the first magnetic field concentrator is a sheet of soft magnetic material with a high permeability. 
     
     
       5. The magnetizing device of  claim 1 , wherein the first magnetic field concentrator deflects a plurality of magnetic field lines of the magnetic field to concentrate the magnetic field at a side of the first magnet facing the transport direction. 
     
     
       6. The magnetizing device of  claim 1 , wherein a surface of the first magnetic field concentrator is spaced apart from a surface of the first magnet and an air gap is formed between the first magnetic field concentrator and the first magnet. 
     
     
       7. The magnetizing device of  claim 1  wherein a surface of the first magnetic field concentrator is directly adjacent to a surface of the first magnet. 
     
     
       8. A magnetizing device comprising
 a first magnet and a second magnet each having a magnetic field forming a magnetization region in which a magnetizable security element is exposed to a magnetic field strength having a defined magnetic field direction, wherein the magnetic field is parallel tangential to a transport direction of the magnetizable security element on an upper side and a lower side of the magnetizable security element; 
 a first magnetic field concentrator and a second magnetic field concentrator each formed of a ferromagnetic material, the first and second magnetic field concentrators arranged in the magnetic field and adapted to focus and amplify the magnetic field in the defined magnetic field direction in the magnetization region to result in a stronger magnetic field on both an upper side and a lower side of the magnetizable security element. 
 
     
     
       9. The magnetizing device of  claim 8 , wherein the first magnet and the second magnet face each other in the magnetization region, with the first magnet arranged on a first side of the magnetization region and the second magnet arranged on a second side of the magnetization region opposite the first side. 
     
     
       10. The magnetizing device of  claim 9 , wherein a north pole of each of the first magnet and the second magnet points toward the magnetization region, and a south pole of each of the first magnet and the second magnet points away from the magnetization region. 
     
     
       11. The magnetizing device of  claim 9 , wherein a south pole of each of the first magnet and the second magnet points toward the magnetization region, and a north pole of each of the first magnet and the second magnet points away from the magnetization region. 
     
     
       12. The magnetizing device of  claim 1 , wherein the first magnet and the first magnetic field concentrator are enclosed by a housing formed of a die-cast zinc. 
     
     
       13. The magnetizing device of  claim 1 , further comprising a further magnet arranged downstream of the first magnet in the transport direction. 
     
     
       14. The magnetizing device of  claim 8 , further comprising a further pair of magnets arranged downstream of the first magnet and the second magnet in a transport direction in which the magnetizable security element is transported through the magnetization region. 
     
     
       15. The magnetizing device of  claim 14 , wherein the further pair of magnets have a reverse polarization to the first magnet and the second magnet. 
     
     
       16. The magnetizing device of  claim 15 , wherein the further pair of magnets have a magnetic field strength less than the first magnet and the second magnet. 
     
     
       17. A method for magnetizing a security element, comprising:
 forming a magnetization region with a first magnet in which the security element is exposed to a magnetic field strength having a defined magnetic field direction; and 
 focusing and amplifying the magnetic field in the defined magnetic field direction to result in the magnetic field being stronger and tangential to a transport direction of the magnetizable security element in the magnetization region with a first magnetic field concentrator, wherein the first magnetic field concentrator is formed of a ferromagnetic material and is disposed in the magnetic field. 
 
     
     
       18. The method of  claim 17 , further comprising a second magnet with a second magnetic field concentrator, the first magnet with the first magnetic field concentrator forms the magnetization region with the second magnet and the second magnetic field concentrator. 
     
     
       19. The method of  claim 18 , further comprising forming a further magnetization region with a further pair of magnets arranged downstream of the first magnet and the second magnet in a transport direction in which the security element is transported through the magnetization region, the further pair of magnets have a reverse polarization to the first magnet and the second magnet and have a magnetic field strength less than the first magnet and the second magnet.